RIO DE JANEIRO - Brazil is hit again by an outbreak of dengue fever, Health Minister Alexandre Padilha said on Monday.

"There's no doubt that we have an epidemic of dengue fever, (as) we have in every summer," said Padilha.

The health ministry announced earlier in the day that the number of cases in the first seven weeks of 2013 reached 204,640, up 190 percent from the same period of last year.

The minister said that while 83 percent of the cases were concentrated in eight states, the other states should continue their anti-dengue campaign.

Mato Grosso in the midwest region is the hardest-hit state with 42,015 cases, followed by the southwestern state Minas Gerais, with 35,334.

Though the number of dengue cases is higher this summer, the death toll is lower, standing at 33, down from 41 in the same period of 2012, and the number of severe cases fell from 577 to 324, the government said.

Padilha attributed the declining death rate to better treatment and reduced waiting time for both treatment and correct diagnosis.

He said that the higher number of infected cases was mostly due to the spread of type-4 dengue, which was first detected in Brazil in 2011.

There are four known types of dengue fever, and once a person is infected by one type, he or she becomes immune to that variation. Since the type-4 dengue is new to Brazil, most of the people are vulnerable, Padilha explained, warning that, "The whole country is susceptible."